Wallboard joint system



M r 9 D. D; CRANDELL 2,313,990

WALL BOARD JOINT SYSTEM Filed April 25, 1941 INVENTOR DFA/V 0. (RAM 05MATTO NEY5 Patented Mar. 16, 1943 wanmoaitn Jomr SYSTEM Dean D. Crandell;Buflalo, N. assignor to Na: tional Gypsum Company, Buffalo N. Y.

Application April 23, i941 ,seria'1 No. 389,909 6 Claims. '(Cl."l216)'This invention relates to building wall constructions and particularlyto'jwall constructions composed of individual panel sections mountedwith their edges in abutting relation, whereby a joint is formed overwhich it is desired to place a concealingand reinforcing member.

'Hereto'fore it has. been proposed to use paper tape having featherededges and having a strength along one axis greaterthanthe strength alongan axis at right angles thereto As it is customary to place cement underthis tape and in many instances'over the tape whereby the same-becomesdamp, the tape is subject to shrinkage with the result that hair-linecracks develop alongthe edges.-

It has also been suggested'toemploy perforated metal strips as jointreinforcing members. How-' ever, a construction in which a metalstrip'of' this type is employed does not dry out' properly due to the factthat the impervious metal tape seals moisture thereunder and the jointcement dries imperfectly and irregularly;

It has also been proposed to'use, wire fabrics as joint reinforcingmembers. In addition to the excessive thickness of the fabric whichrenders it extremely difficult to produce a decorative ef feet over thistype of reinforcing member. withnut'the necessity of plastering, 'it isdiflicult to form such tapes intoreinforcing elements suitable for usefor interior or exterior corners. In

addition, these tapes are'very costly and are not economical in use. Y

It is an object of the present invention to provide a joint reinforcingmember and a wall constructlon employing the same wherein substaniiallyall of the defect of the prior reinforcing members and resultantconstructions are eliminated.

V It is also an object of the invention to provide a reinforcing jointmember possessing a tensile strength considerably greater than thetensile strength. of acceptable members heretofore proposed. Y j y y Itis an additional object of the invention to provide a joint reinforcingelement or member that i impervious in itself to moisture and yetpe'rmit's ready evaporation of moisture therethrough and a member whichis flexible and resilient and an element in fabric form which is notsubject to the shrinkage encountered heretofore in the use of theavailable types of fabrics.

According to the present invention novel means are provided for treatingthe joints or cracks between adjacent substantially abutting panels insuch a wayas to conceal such joints or' cracks and provide reinforcementthereacross as well as to facilitate painting or decorating the surfaceof the wall formed by the panels without the necessity for applying acoat of plaster or emplaying other means for rendering the joints orcrackspermanently invisible, The novel means which the present inventionaffords comprises a tape or ribbon of novel construction for securementover joints or cracks by adhesion or the like.

In its preferred form the tape or ribbon comprises a' body'formed of astrip of glass fabric, that is, a strip of woven textile or the likematerial formed fromv threads of spun glass. In another form my improvedjoint reinforcement may comprise a conventional textile fabricincluding, partially, spun glass threads. Specificaliy, I have foundthat satisfactory results maybe attained by using ordinary cotton orother usual textile fiber for the warp threads running longitudinally ofthe tape, with glass threads comprising the weft threads runningtransversely of the tape. In one contemplated form of the'pres'entinvention the individual threads comprising the glass fabric are coated,usually by spraying or dipping, with either ,a thermo-plastic or athermo-settlng resin. The resin employed may be either natural orsynthetic. significant advantages are gained by the use of the fabricwoven of wholly or partly spun glass threads due to its lack of stretchand also due to its non-absorbent nature and its chemical inertness.

. When used, the resin coating is of'such thickness, with respect to thecount of the fabric and the diameter of the individual threads, as toleave the finished article porous. That is, the resin does not'tend toproduce a flat impervious ribbon. When the glass fabric is coated withresin as contemplated in one form of the present invention thetendency'of warp and weft threads to shift relatively to each otherunder strain is even more thoroughly eliminated than by the use of anuncoated strip of glass fabric although certain of the advantages of thepresent invention may be attained without coating the glass fabric.

In the drawing: I v Fig. l is a perspective view of a wall constructionembodying the principles of the present invention and with portionsbroken away for clearness; and v Fig. 2 is a cross-sectional view, on agreatly enlarged scale, of a piece of crack covering materialconstructed in accordance with one form of the teachings of myinvention.

vIn the drawing like characters of reference denote like parts and thenumeral l designates wall boards secured to building framework which maybe in the nature of studding I l. The securement of the wall boards maybe by any means conventional in the art. In the drawing nails 12 areshown for providing such securement. A seam ii of varying width willgenerally appear at the point of approximate abutment of adjacent panelsl0.

The improved joint reinforcing tape I4 is placed over the Joint l3whereby the marginal edges of the tape engage the abutting wall boards.Generally, joint [3 will be filled with a joint filler cement of anyconventional type or composition and in addition a layer of the cementis spread over the exposed surface of the reinforcing memher M. Ingeneral, the layer of cement over the exposed surface of the reinforcingmember I4, indicated at IS in Fig. 1 of the drawing, will be thinned outat the edges on application or sanded I down in order not to form aheavy or jagged edge which might be exposed through a decorative coatingof, for instance, paint applied over the wall board and the jointsystem.

The improved Joint tape may also be employed as a reinforcing elementwithout the necessity of filling open joint l3 with joint filler. cementdue to the superior strength, rigidity and yet inherent flexibility ofthe fibers from which the tape is made. In such an instance the tape isapplied and held in place with a suitable type of glue, as, forinstance, a casein base glue or other suitable glues.

The improved joint tape reinforcing element is, in one form, made ofglass fiber woven to the desired mesh size and using individual fibersof the desired thickness. In general, the total thickness of the tapeshould not exceed about 0.015, and the tape found most satisfactory willhave a thickness bf from about 0.009 to 0.012 of an inch. It is to beunderstood that the mesh of the fabric is preferred to be relativelyopen. I have found a mesh of, around 14 threads to the inch highlysatisfactory.

Although the woven glass fabric is eminently suitable as a jointreinforcing element by itself, under some conditions it may be desirableto add additional rigidity to the tape in order to prevent anysuggestion of sagging of the tape in the joint in instances where thejoint may he of conpull exerted in a direction transverse to the extentof the tape or, so to speak, across the Joint.

The foregoing specific description is not to be considered as limitingthe scope of my invention thereto, or otherwise than as defined in theappended claims.

What is claimed is:

1. In a wall construction, a supporting member, panels secured fiatwiseagainst said supporting member in substantially edge to edge relation toform a wall board joint, and a tape of spun glass threads woven to forma fiat fabric placed over said joint, said tape being attached to theouter surface across the edges of adjacent panels with an adhesivebonding agent.

2. In a wall construction, a {supporting member, panels secured fiatwiseagainst said supporting member in substantially edge to edge relation toform a wall board joint, anda tape of spun glass threads woven to form aflat fabric placed over said 'joint, said tape being attached siderablewidth. In order to produce a tape of interstices are not clogged withthe glue or cement.

The relative proportion of fiber or thread thickness, pitch of threads,and coating thickness, when a coating is used, are all shown in apreferred form in Fig. 2 of the drawing. In

Fig. 2 the numeral I 8 designates warp and weft threads of. glass andthe numeral l9 refers to the coating applied thereto. I

While the embodiment specifically described has been referred to ascomprising glass threads en'- to the outer surface across the edges ofadjacent panels withan adhesive bonding agent, the diameter of thethreads of the fabric being less than the pitch of adjacent threads soas to leave substantial interstices therebetween.

3. In a wall construction, a supporting member, panels secured flatwiseagainst said supporting member in substantially edge to edge relation toform a wall boardjoint, and a tape of spun glass threads woven to form afiat fabric secured over said joint, the threads of said fabric beingprovided with a surface coating of a stiffening agent.

4. In a wall construction, a supporting member, panels secured flatwiseagainst said supporting member in substantially edge to edge relation toform a wall board joint, and a tape of spun glass threads woven to forma fiat fabric secured over said joint, the diameter of the threads ofthe fabric being less than the pitch of adjacent threads as to leavesubstantial interstices therebetween. said fabric being provided with a.surface coating of a stiffening agent of such thickness as not to fillsaid interstices.

5. In a wallconstruction, a supporting member, panels secured fiatwiseagainst said supporting member in substantially edge to edge relation toform a wall board joint, and 'a tape of woven fabric placed over saidjoint and secured ,across the edges of adjacent panels with an adhesivebonding agent, said tape having weft threads of spun glass.

6. In a wall construction, a supporting member, panels secured fiatwiseagainst said supporting member in substantially edge to edge rela-

